Pannexin1: a multifunction and multiconductance and/or permeability membrane channel
1Department of Physiology and Biophysics, University of Miami School of Medicine , Miami, Florida.
American Journal of Physiology. Cell Physiology
|May 3, 2018
Summary
The pannexin1 (Panx1) channel, when cleaved by caspase 3, is primarily selective for chloride ions and does not release ATP. This challenges previous assumptions about the function of activated pannexin1 channels.
Area of Science:
- Molecular Biology
- Cell Signaling
- Ion Channel Physiology
Background:
- Pannexin1 (Panx1) is a well-characterized pannexin involved in cellular signaling.
- Panx1 is generally accepted to function as an ATP release channel, but its permeability varies with stimuli.
Purpose of the Study:
- To investigate the biophysical properties of the caspase-cleaved pannexin1 channel.
- To clarify the ATP permeability and ion selectivity of Panx1 after caspase 3 cleavage.
Main Methods:
- Utilized a truncation mutant (Panx1Δ378) mimicking caspase-cleaved Panx1.
- Performed biophysical characterization of channel activity, ion selectivity, and permeability.
Main Results:
- The Panx1Δ378 channel exhibited constitutive activity.
- The channel demonstrated high chloride selectivity and lacked cation permeability.
- ATP release was not observed unless stimulated by extracellular potassium ions.
Conclusions:
- The caspase-cleaved Panx1 channel is primarily selective for chloride ions.
- Contrary to previous claims, the caspase-cleaved Panx1 channel is likely impermeable to ATP under basal conditions.
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